Moshe Armon1, Francesco Marra2,
Yehouda Enzel1, Dorita
Rostkier-Edelstein1,3, Chaim I.
Garfinkel1, Ori Adam1, Uri
Dayan4, Efrat Morin1
1Fredy and Nadine Herrmann Institute of Earth
Sciences, the Hebrew University of Jerusalem, Jerusalem, 9190401, Israel
2National Research Council of Italy, Institute of
Atmospheric Sciences and Climate, CNR-ISAC, Bologna 40129, Italy.
3Department of Environmental Physics, Environmental
Sciences Division, IIBR, Ness-Ziona 7410001, Israel.
4Department of Geography, the Hebrew University of
Jerusalem, Jerusalem, 9190401, Israel.
Corresponding author: Moshe Armon
(moshe.armon@mail.huji.ac.il)
Key Points:
- End of 21st century heavy precipitation events in
the eastern Mediterranean are projected to have substantially reduced
rainfall yield
- This reduction results mainly from a major decrease in rain area
during future events, despite the increased conditional rain rate
- Changes in rain yield, rate, and area are consistent across many
events, suggesting great hydrological implications for the region
Abstract
Heavy precipitation events (HPEs) can lead to deadly and costly natural
disasters and are critical to the hydrological budget in regions where
rainfall variability is high and water resources depend on individual
storms. Thus, reliable projections of such events in the future are
needed. To provide high-resolution projections under the RCP8.5 scenario
for HPEs at the end of the 21st century and to
understand the changes in sub-hourly to daily rainfall patterns, weather
research and forecasting (WRF) model simulations of 41 historic HPEs in
the eastern Mediterranean are compared with “pseudo global warming”
simulations of the same events. This paper presents the changes in
rainfall patterns in future storms, decomposed into storms’ mean
conditional rain rate, duration, and area. A major decrease in rainfall
accumulation (-30% averaged across events) is found throughout future
HPEs. This decrease results from a substantial reduction of the rain
area of storms (-40%) and occurs despite an increase in the mean
conditional rain intensity (+15%). The duration of the HPEs decreases
(-9%) in future simulations. Regionally maximal 10-min rain rates
increase (+22%), whereas over most of the region, long-duration rain
rates decrease. The consistency of results across events, driven by
varying synoptic conditions, suggests that these changes have low
sensitivity to the specific large-scale flow during the events. Future
HPEs in the eastern Mediterranean will therefore likely be drier and
more spatiotemporally concentrated, with substantial implications on
hydrological outcomes of storms.